On Threat Matrix, a disappontment despite the presence of Kelly Rutherford*, there was a suicide bomber with an undetermined amount of C4 strapped to his chest. A simulation of what the bomb would destroy showed that two pounds would wipe out the floor of the building, five pounds would take down the building, and ten pounds would take down the block.
Points:
He was detonating it on the floor of the New York Stock Exchange, a large, open space. He was intending to take out visiting dignitaries in the balcony but I assume that the lion’s share of injuries would come from shrapnel and not the blast itself.
In one of the high points of my Boy Scouts career an Army demolition team gave us a demonstration by blowing up a pond (you just don’t have fun like that in the Modern Boy Scouts, I fear). A quarter-pound block of C4 blew up real good, sending a spout water about thirty feet in the air, but extrapolating from that ten pounds, even placed optimally, would be unlikely to take down a block full of buildings made of steel, stone, and reinforced concrete.
Was TV lying to me?
You may remember her from Briscoe County. I know I do. My wife ruined Threat Matrix for me when she said, “I recognized her even despite all the plastic surgery she’s had,” and I spent the rest of the episode trying to figure out what she had done.
In other words, there ain’t NO way ten pounds is taking out a block of buildings. I guess I go back to having nothing to watch at 8PM/7PM Central Thursdays.
For comparison, the bomb that took out a hotel in Baghdad was 500 pounds of C-4. A general guideline for a concrete wall breach about 16 inches thick is 10 pounds. That will create a hole about 30 inches across. A standard is for 8 inches of reinforced concrete, 2 1/2 pounds will blow a hole roughly a foot across.
Actually, I believe that they said something like “The analysis came back, and this stuff is like C4 (or maybe it was Syntex) on steroids.” The point is, the stuff wasn’t C4. It was a fictional super-mega-ultra plastic explosive.
The reason that composition C4 is so widely used is its stability. Outside of severe shock events as would be produced with blasting caps, C4 can be handled quite safely. The actual explosive agent in C4 is, I believe, RDX or something similar. RDX itself has a theoretical explosive yield much greater than trinitrotoluene (TNT), but is very dangerous stuff due to its volatility.
As for taking down a building with C4, it is true that you don’t need much, but what you do need is experienced demolition personnel to place the charge(s) in the most critical structural locations within the building, and the charges themselves need to be shaped to focus the pressure wave in a manner most likely to rupture the target structure. Properly shaped charges, properly located, can do orders of magnitude more damage than a lump of explosive detonated in any random location.
A suicide bomber with a load of C4 strapped to his body would, as you surmised, accomplish much more by detonating himself in a location prone to produce shrapnel.
Ten pounds could do it, if placed inside crucial structural elements. After all you only have to destroy the first floor, Isaac Newton takes care of the rest.
To do the job with ten pounds you would need a professional demo crew, but technically it could be done.
As you might have guessed, there was a point where I stopped paying much attention to a disappointingly silly show. Although I WAS wondering why the NYSE was looking so much like the Chicago exchange.
I am familiar with the buildings on that block and I fear the Loizeaux family themselves would have trouble dropping them with a mere ten pounds of anything unless the buildings had been throughly prepped and the structures weakened.
finally something I know about, or cooking with C4.
It wasn’t only the special forces doing it, I was a straight leg infantry medic and we used it. Like Uncle Bill said, it was safe as long as you didn’t stomp on it while it was burning. We usually used it to heat water for C-ration coffee because it was so hot. We would use the heat tabs for the C-rations themselves if we had them rather than the C4.
C4 burns with a yellow flame, but inside the yellow flame are streaks of blue. For this reason we would shape the C4 into a mushroom and light it. The blue streaks would go straight up from the top of the mushroom shape, but from the bottom of the mushroom shape, the blue streaks would bend up. remember, we didn’t have anything to distract us (two books in my entire company)and had to find our entertainment where we could.
If you manipulated the C4 too long, some chemical would cross the barrier of skin and give you a glorious headache.
How powerful an explosive is Semtex in comparison with dynamite? Also, is it the same thing as plastic explosives/plastique that I occasionally hear about in the movies?
As an aside, explosives don’t generate a great deal of flame. Movies tend to show explosions with a big fireball, but real world explosives go off with their energy directed toward high pressure gas.
Another nitpick it wasn’t the Chicago stock exchange. It was the Chicago commodities exchange. Stocks are traded on the New York Stock Exchange (NYSE), the American Stock Exchange (AMEX) and electronically through the National Association of Security Dealer’s Automated Quotation service (NASDAQ) Over-the-Counter (O-T-C).
I watched the episode and found it to be a bit lame. Especially the part with the bees in the missile silo. Hey, networks are trying to entertain us and keep things vague enough not to jepardize national security at the same time.
I believe the headache is caused by the nitroglycerine. I read an article a while back (Discover?) where the journalist went to an explosives factory. The same effect (dialiation of blood vessels?) that makes it useful in heart medication gives you a headache. Apparently the workers get used to it.
The only other thing I remember about the article is that doors in those places are big and swing outwards.
In general, Semtex is nearly identical as C4 in power. There are various grades of Semtex, which basically have different levels of PETN in the mix. It is generally a bit more sensitive than C4, and can be worked a little bit easier, but overall, it’s the same stuff as far as use. And yes, Semtex or C4 is usually what is being used when people mention “plastique” as they are the most common.
Although I WAS wondering why the NYSE was looking so much like the Chicago exchange.